Embodiments of the present invention generally relate to imagers and sensors. More specifically, certain embodiments relate to light guided pixels, light guided pixel devices, and light guided pixel systems for bright field and fluorescence/phosphorescence imaging.
In addition to bright field imaging, fluorescence/phosphorescence imaging can be crucial to study or monitor structural and functional morphology of biological samples in biomedicine and biological sciences. For example, fluorescence/phosphorescence imaging techniques can be used to identify or detect microscopic structures, submicroscopic structures, even individual molecules in biological samples.
Conventional fluorescence microscopes are common tools that use fluorescence imaging to investigate biological problems. Typically, a fluorescence/phosphorescence dye is mixed with a specimen to mark or tag portions of the specimen(s) (e.g., cell(s)) under investigation with fluorophore(s). A fluorophore refers to a component of a molecule that causes the molecule to fluorescence or phosphorescence once excited. A fluorophore can absorb energy from excitation light of a specific wavelength(s) and re-emit the energy at a different wavelength(s). The conventional fluorescence microscope irradiates the sample with excitation light of predetermined wavelength(s) (e.g., blue light) to activate fluorophore(s) in the sample. In response, fluorophore(s) release fluorescence/phosphorescence emissions of different wavelength(s) (e.g., green light). The emissions are usually much weaker than the excitation light and are scattered from each fluorophore.
Most conventional fluorescence microscopes have a filter between the sample and the detector surface. The filter absorbs or reflects the excitation light and passes the weaker fluorescence/phosphorescence emissions of different wavelengths to the sensor. When using conventional absorptive dyes, the filter may be designed with a thickness of more than a few micrometers due to attenuation coefficients. The diffraction, interference, and scattering of the weak emission signal within the filter can degrade resolution of the fluorescence images.